Liver - Extramedullary Hematopoiesis
comment:Extramedullary hematopoiesis is unexpected in adult rodents and is typically associated with pathologic conditions. It is distinguished from inflammatory cell infiltrates by the presence of nucleated erythrocytes, immature granulocytes, and/or undifferentiated progenitor cells in the absence of associated hepatocellular necrosis. Clusters of erythroid cells are present in Figure 1 and Figure 2 (arrows). It is most often seen in animals treated with a toxicant and may be associated with hepatocellular degeneration, pigment deposition, and/or fatty change ( Figure 2 ). A megakaryocyte is present in Figure 2 (arrowhead). Multiple perivascular cellular accumulations in Figure 3 and Figure 4 consist predominantly of developing granulocytes.
recommendation:Whenever present, extramedullary hematopoiesis should be diagnosed and graded. Examination of bone marrow, lymph node, and spleen sections may show a correlation with extramedullary hematopoiesis in the liver. The types of cells involved (e.g., erythroid, granulocytic, mixed) should be indicated in the pathology narrative if they can be identified.
related links:Adrenal Gland - Extramedullary Hematpoiesis
Spleen - Extramedullary Hematopoiesis
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